RNAi agents for maintenance of stem cells

Abstract

The present invention provides compositions and methods suitable for delivering RNAi agents against genetic targets in stem cells so as to direct cell growth and differentiation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims benefit of U.S. Provisional Patent Application Ser. No. 60 / 641,929, filed Jan. 6, 2005, which is herein incorporated by reference.BACKGROUND OF THE INVENTION [0002] Utilization of double-stranded RNA to inhibit gene expression in a sequence-specific manner has revolutionized the drug discovery industry. In mammals, RNA interference, or RNAi, is mediated by 15- to 49-nucleotide long, double-stranded RNA molecules referred to as small interfering RNAs (RNAi agents). RNAi agents can be synthesized chemically or enzymatically outside of cells and subsequently delivered to cells (see, e.g., Fire, et al., Nature, 391:806-11 (1998); Tuschl, et al., Genes and Dev., 13:3191-97 (1999); and Elbashir, et al., Nature, 411:494-498 (2001)); or can be expressed in vivo by an appropriate vector in cells (see, e.g., U.S. Pat. No. 6,573,099). [0003] In vivo delivery of unmodified RNAi agents as an effective therapeutic for use in h...

AI Technical Summary

Benefits of technology

[0010] The present invention provides stable, effective siRNA and ddRNAi reagents and methods for use thereof to control the differentiation and proliferation of stem cells by altering the level of expression of one or more transcriptionally active genetic regions that are directly or indirectly associated with the differentiation and proliferation of stem cells.

[0011] The present invention provides a method for controlling differentiation and proliferation of stem cells together with genetic agents for use therewith, as well as genetically modified cells comprising the genetic agents. The present invention would allow for the in vitro proliferation of stem cells for research purposes. Another aspect of this invention would allow for the ex vivo stimulation of stem cells to differentiate to a particular path of progenitor cells. The present invention is predicated in part on the use of genetic agents that facilitate gene silencing via RNAi to downregulate or silence one or more transcriptionally active genetic regions directly or indirectly associated with the differentiation and proliferation of stem cells. Such transcriptionally active regions are also referred to herein as “stem cell associated genetic targets” or “SCATs”. siRNA and ddRNAi-mediated silencing of one or more SCATs effects control of the proliferation of stem cells in a subject or cell culture.

Problems solved by technology

In vivo delivery of unmodified RNAi agents as an effective therapeutic for use in humans faces a number of technical hurdles.

Efforts have been made to increase stability of injected RNA by the use of chemical modifications; however, there are several instances where chemical alterations led to increased cytotoxic effects.

Clinical and basic investigators share the same fundamental problem—limited ability to grow and expand the numbers of human HSCs.

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